The overall purpose of the present study is the investigation of the relationships between brain proteins and lipids. Primary emphasis is placed on the chemistry of myelin proteins and particularly proteolipids. During the coming year the major effort will be directed towards the long range goal of determining the amino acid sequence of the proteolipid protein. The first step towards that goal will be to obtain a protein which is homogeneous by end group analysis and polyacrylamide gel electrophoresis. Techniques to be used include a) preparative gel electrophoresis, b) isoelectric focusing, c) column chromatography in the presence of various detergents, and d) preparation of chemically modified proteolipids. Concomitantly, the action of various proteolytic enzymes on proteolipids and chemically modified proteolipids will be studied and techniques for the isolation of peptides from these preparations developed. An additional line of investigation will be the systematic study of the properties of the enzyme 2'3' cyclic nucleotide 3' phosphohydrase in myelin and, for comparison, in erythrocyte ghosts.